Patent US3760419A successfully refreshed from Google Patents.
US3760419A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ideband power in ils navigation systems method of and arrangement for varying the ratio of carrier power to s
Assignee: International Standard Electric Corp
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Filing: 1972-02-03
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Granted: 1973-09-18
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Expires: 1992-02-03
Abstract
Abstract A device for simply and inexpensively controlling the ratio of carrier to sideband power is an ILS ground transmitting station or the like. Two RF outputs are supplied, one providing center antenna excitation and the other providing sideband antenna excitation. The transmitter output stages are amplitude modulated by modified modulation signals which are produced by summing the original modulation tones with adjustable fractions of the difference thereof. A simple potentiometer control provides the adjustment, which controls beam pattern sharpness to accommodate different length runways.
Inventors
- 👤 W Poschadel
- 👤 G Hofgen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:13
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
191 words
A method of varying the ratio of carrier to sideband power in an ILS navigation transmitting station for producing depth of modulation patterns, said transmitting station providing for an antenna radiating system fed from two opposite points of a modulation bridge, the other pair of opposite points of said bridge being excited from dual, separately modulated transmitter RF outputs, comprising: differencing first and second modulation signals having first and second corresponding frequencies to produce a modulation difference signal; deriving a modulation inverse difference signal by inverting said modulation difference signal; deriving a controllable scale factor difference signal consisting of a variable proportion of said modulation difference signal and said inverse difference signal; adding said scale factor difference signal to said first modulation signal to produce a modified first modulation signal; deriving and adding the inverse of said scale factor difference signal to said second modulation signal to produce a modified second modulation signal; and applying said modified first and second modulation signals to modulate corresponding ones of said transmitter RF outputs, the controllability of said controllable scale factor difference signal thereby providing control over said ratio of carrier to sideband power.
Claim 2
Independent Claim
191 words
A method of varying the ratio of carrier to sideband power in an ILS navigation transmitting station for producing depth of modulation patterns, said transmitting station providing for an antenna radiating system fed from two opposite points of a modulation bridge, the other pair of opposite points of said bridge being excited from dual, separately modulated transmitter RF outputs, comprising: differencing first and second modulation signals having first and second corresponding frequencies to produce a modulation difference signal; deriving a modulation inverse difference signal by inverting said modulation difference signal; deriving a controllable scale factor difference signal consisting of a variable proportion of said modulation difference signal and said inverse difference signal; adding said scale factor difference signal to said first modulation signal to produce a modified first modulation signal; deriving and adding the inverse of said scale factor difference signal to said second modulation signal to produce a modified second modulation signal; and applying said modified first and second modulation signals to modulate corresponding ones of said transmitter RF outputs, the controllability of said controllable scale factor difference signal thereby providing control over said ratio of carrier to sideband power.
Claim 3
Dependent Claim
200 words
In an ILS navigation ground station for transmitting beams of radio frequency energy modulated by first and second modulation frequency signals, apparatus for controlling the ratio of carrier power to sideband power comprising: means responsive to said first and second modulation signals for producing a signal representative of the difference thereof as a first difference signal; an impedance element having a movable tap adjustable over at least a portion thereof; means for applying said difference signal to one end of said impedance element and the inverse of said difference signal to the other end thereof, whereby a second difference signal is available at said tap as the product of said first difference signal and a scale factor which is a function of the setting of said tap; means for adding said second difference signal to said first modulation signal and the inverse of said second difference signal to said second modulation sigNal to produce modified first and second modulation signals; radio frequency generating means having first and second RF output channels each adapted to be separately modulated; and means for applying said modified first and second modulation signals to said first ans second RF output channels, respectively, as modulation thereon.
Claim 4
Dependent Claim
200 words
In an ILS navigation ground station for transmitting beams of radio frequency energy modulated by first and second modulation frequency signals, apparatus for controlling the ratio of carrier power to sideband power comprising: means responsive to said first and second modulation signals for producing a signal representative of the difference thereof as a first difference signal; an impedance element having a movable tap adjustable over at least a portion thereof; means for applying said difference signal to one end of said impedance element and the inverse of said difference signal to the other end thereof, whereby a second difference signal is available at said tap as the product of said first difference signal and a scale factor which is a function of the setting of said tap; means for adding said second difference signal to said first modulation signal and the inverse of said second difference signal to said second modulation sigNal to produce modified first and second modulation signals; radio frequency generating means having first and second RF output channels each adapted to be separately modulated; and means for applying said modified first and second modulation signals to said first ans second RF output channels, respectively, as modulation thereon.
Claim 5
Dependent Claim
45 words
Apparatus according to claim 2 in which said means for producing a signal representative of the difference of said first and second modulation signals is a differential amplifier and said means for adding said second difference signal to said second modulation signal includes an inverter.
Claim 6
Dependent Claim
52 words
Apparatus according to claim 2 including a radio frequency bridge, one pair of opposite points of which is excited from said first and second RF output channels and the other pair of points of which separately provides the sum and difference of the modulated RF outputs of said radio frequency generating means.
Claim 7
Dependent Claim
22 words
Apparatus according to claim 3 in which said impedance element consists of a potentiometer having substantially only a resistive component of impedance.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |